Gas turbine motor plant



A March 20, 1945.

L. A. HERMITTE GAS TURBINE MOTOR PLANT 2- Sheets-Sheet 1 Filed Jan. 26, 1942 .,ZJN.

I@ j@ df l d. Rw M www m im FW March 20, 1945. L. A. HERMITTE 2,371,889

GAS TURBINE MOTOR PLANT Filed Jan. 2e, 1942 2 sheets-sheet 2 i .Rz ,5 G 'im ta C M 2" v Patented Mar. 20, 1945 GAS TUnlNE Mo'ron PLANT Louis Armand Hermitte, La Courneuve, France; vested in the Alien Property Custodian Application January 26, 1942, Serial No. 428,304

, In France January 10, 1941 (Cl. .B-4.1)

7 Claims.

My invention a-pplies more particularly to those gas turbine motive systems in which the com- .pressor or compressorsvare driven by one or more auxiliary turbines which are mechanically independent of the motive turbines.

In what follows, it will be supposed for the sake of simplicity that there is only one motive turbine driving a receiving apparatus and only one auxiliary turbine driving an air compressor.

Such a system may be controlled in different ways all of which amount to-acting on the sup- `ply of fuel by adapting it to the load borne by the receiving apparatus. The auxiliary turbocompressor set then assumes a Speed which is a function of this load.

The speed with which the power furnished by the motive turbine can be increased is in relation with-the mechanical inertia of the auxiliary set and with the inertia of the iluid columns incolumns involved which are practically negligi-` ble.

'I'his adjustment is suitable in those cases where the variations of speed are important and can not be foreseen. For reduced loads, the yield of a gas turbine motor thus adjusted is inferior to that of a motor in which the Speed of the auxiliary set is free or is adjusted in order to obtain at the turbines that maximum temperature compatible with their good mechanical behavior.

Whenever periods of load variation are separated by rather long periods of operation at rated load and that in the course of these periods it is possible to foresee the coming variations of load, it is advantageous to be able to momentarily suppress the action of the constant speed con` trol of the auxiliary set, it being necessary to have recourse again to this constant speed control only when load variations are expected.

In its second embodiment, the invention comprises a system which enables the effecting of these operations and which is superadded to the speed control of the auxiliary set.

The applying of the invention to that case where the motive turbine and the auxiliary turbine are fed by one and the same combustion chamber, whether these turbines be in parallel or in series requires a device which permits the variation of the distribution of power between these turbines. k l

Whatever be the connection of the turbines (parallel or series), the distribution of power between the turbines can always vbe modified by varying the .cross-section of the inlet tuyres of the turbines, which is a particularly radvantageous method as far as the yield is concerned. It is also possible to transfer power from one shaft to another by means of an electric motor set on the auxiliary shaft and of a generator on the shaft of the motive turbine.

When the turbines are in parallel, it is possible to vary. the power distribution by a gas supply reducing means set above or below one of them. With turbines mounted in parallel another advantageous embodiment consists in supplying them by means of two distinct combustion chambers. the fuel supply to each of these chambers being adjusted for each turbine,according to the respective powers.

, In the case where two distinct ycombustion chambers are utilised. the speed governor of the auxiliary set controls the supply of -fuel to the combustion chamber of the auxiliary turbine.

while the control organ for the load acts on the fuel supply to the combustion chamber of the motive turbine.

With a view to increasing the speed with'which the new state of equilibrium corresponding to any load variation whatever can be attained, it is important that the control organ for the load of the set, while acting on the supply of fuel toF the burners, also obtain an approximate adjust! ment of the power distribution to the two tu'rbines. The speed governor of the auxiliary set has then onlyto perfect this latter adjustment.

The description which follows, with reference to the appended drawings, given by way of. nonlimitative example, will allow a thorough understanding of how the invention can be embodied, those characteristics which appear in the drawings as well as' in the text being a part, of course, of the invention. y

Figure 1 is a diagrammatic view of one embodiment of the invention illustrative of the rst described mode of operation;

Figure `2 is a somewhat more diagrammatic view showing the main and auxiliary turbines connected in series, electrical controls being employed instead of the linkagesA used in the other embodiments;

Figure 3 is a smaller view showing a modied form of apparatus employing two combustion chambers. but utilizing the same form of opera.- tion as the device in Figure l;

Figure 4 is a fragmentary view of an adjusting device interposed between the governor of the auxiliary set and the linkages employed in the embodiments shown in Figures 1 and 3; and

Figure 5 is a chart indicating the speed and load variations for various adjustments of the device shown in Figure 4.

Fgure 1 represents a gas turbine motive system in which the motive turbine tm and the auxiliary turbine ta are mounted in parallel, a single combustion chamber ch being utilized. The receiving apparatus r is supposed to be a constant speed electric generator.- The load controlling member is the speed governor R1 of the motive turbine tm; the movable .portion |00 of the governor R1 acts directly on the supply of .fuel to the burner b through the linkage l l0 connected to thefuel valve lli in the pipe lll-a leading into the combustion chamber ch. The member which varies the power distribution between the two turbines is, for example, the obturator or valveO controlling the passage of the gases to the inlet end of the auxiliary turbine ta. 'I'he adjustment of the obturator is made to depend upon both the speed governor Rz of the auxiliary turbine and upon the main governor R1. This is accomplished by pivotally connecting the valve O to an intermediate .point on the iloating leverp by means of the linkages H3.

-The temperature, which was less than the maximum allowable. rises, the temperature drop of the motive turbine increases and consequently the power it supplied also. Simultaneously, the lever L reduces the power furnished by the generator G (the control` means of the generator G- are weil known and do not need other explanations) and the power developed on the shaft of the motive turbine increases to that extent.

The auxiliary turbine is urged to accelerate on account of its increase in temperature drop. but it is also influenced to slow down on account of the motor and being unloaded, and the governor Ra maintains the normal speed of the auxiliary The movable portion |00 of ,the governor R1 is connected' by means of the linkage Ill withone end of the lever p, and the movable portion H2 of the governor Ra is connected by means of the linkage Ill with. the other v'end of the lever p.

If it be supposed,'for example, that an increase in the load of the receiving apparatus occurs, the speed of the motive turbine tm will have a tendency to fall, and immediately the governor R1 will increase the fuel supply to the burner b and close the obturator O. The tem- Derature which was less than the maximum allowable rises, sin the compressor, maintained at a constant speed, discharges a super-abundant air supply, the temperature drop and the supply of warm gases in the motive turbine increase and the latter, as a result furnishes an increased power. The temperature drop available for the auxiliary turbine also increases, but the supply of warm gases passing through the latter decreases; the auxiliary turbine will vconsequently have a tendency to accelerate or to slow down according to the supply of warm gases passing thereto, the amount being determined by the amplitude of the approximate adjustment obtained and the governor R2 then acts to reestablish a constant speed by adjusting, by means of the oating lever p, the position of the obturator O.

-Figure 2 represents another embodiment of the invention, in which both turbines are in series and where the control of the speed of the auxiliary set is effected electrically. The driven member is, for example, a marine propeller K. An electric generator G is operatively connected with the shaft S of the motive unit tm and an electric motor M2v cemented as by wires 22 to the generator G is mounted on the shaft T of the auxiliary turbine. 'Ihe power supplied by the generator G is controlled by the governor Rz, through movement of the control arrangement tically shown at v by means of a oating lever pl connected by linkage H8 with the governor Rz. For approximate set by adjusting the regulation of the generator G to change the relative inuence of the second factor mentioned.

In the case where the gas turbine should control an electric generator as that designated r' in Figure 1 instead of the propeller K, the power supplied to M could be taken directly from the generator r. ,j

Figure 3 represents another embodiment of the invention, in which two combustion chambers ch1 and cha are utilized, respectively connected to the motive turbine and to the auxiliary turbine which are in parallel. The governor R1 then acts on burner b1 of the motive turbine tm through the linkage H0' connected `with valve ill of the burner b1 while the burner b2 of the auxiliary turbine ta is'dependent upon the two governors- R1 and Rz the latter governor being connected therewith by the linkage H3' connected to one end of the floating lever p' connected to the burner valve HI2. 4

The governor R2 maintains the speed of the auxiliary set constant; the latter consequently furnishes to the combustion chamber of the motive turbine an air supply which is constantfor all loads. The fuel supply being reduced for small loads, the temperature reaches the maximum allowable only under full-load conditions.

When the load is increased, for example, the regulator R1 increases the fuel supply to the burner b1 and temporarily decreases the supply to b2. The temperature of the gases which was less than the maximum allowable increases as well as the temperature drop available and the lpower developed by the motive turbine tm increases. Simultaneously, as a result of the increase in temperature at the turbine tm, the resistance which it chers to the passage oi.' the gases increases and the dischargeof the compressor then has a tendency to preferably enter the auxiliary combustion chamber, which condition would result in a speed variation of the auxiliary set. To maintain it. a new adjustment of the burner b1 is necessary. The governor R1 eiects an approximate adjustment, so that the governor Rz then only has to perfect it. The two governors act on vthe burner bz by means of the floating lever p1, one end of which is connected to the linkage |10' by means of the link age H4.

The three embodiments which have just been described refer to the ilrst mode of realization of the control system consistent with the invention. (Compressor maintained at constant of the auxiliary turbine at a value greater than speed.) In order to pass on to the second mode that which corresponds to the small load and of realization, that is which consists in reducing the speed of the compressor during those periods where the load does not vary, it is necessary to act on the adjustment controlled by the governor Rz. In order to do this, a device such as the one represented in Fig. 4 by way of non,- limitative example, may be utilized. In this device, the movable element II2 of the speed governor R2 of the` auxiliary set rests on the extremity of a balance-lever 8 having an adjustable fulcrum 9, a spring I bearing on the other extremity of the said balance lever, the tension of the said spring being adjusted by mechanism depending upon any characteristic` factor whatever of the load, for example by a. piston II which is subjected to a pressure proportional to the lfuel supply passing through the burner. As illustrated in Fig. 4, a pipe II' is connected with the pipe II I-a leading from the fuel valve III to the combustion chamber ch. This pipe I I communicates with the cylinder II in which slides the piston II.

The fulcrum 9 can be displaced in a slot I3 of the balance lever between the extremities A and B of this slot by means of a nut I2 controlled by a screwed hand-wheel I4.

When the fulcrum 9 is at A, the spring balance lever is non-eifective and the control of the constant speed auxiliary set is obtained (rst embodiment). When the xed fulcrum is displaced from A to B, the further the fulcrum is from A, the greater will the speed of the auxiliary set vary with the load. Practically, it is possible, by displacing this xed fulcrum, to obtain all the curves such as those drawn on Fig. by laying olf as abscissae the load values W of the receiving unit and as ordinates the speed V of the auxiliary set. The straight line a represents constant speed operation and the limiting curve d shows operating conditions obtained when the xed fulcrum is at B. (In this case, the action of the governor and of the spring balance-lever are both nil.) Curves b and c represent intermediate operating conditions when the fixed fulcrum occupies intermediate points between A and B.

What I claim is:

1. The method of operating a thermal gas turbine motor comprising a motive turbine capable of delivering power, an auxiliary turbine mechanically independent of the motive turbine, an air compressor driven by the auxiliary turbine and supplying air to the said turbines and a combustion chamber utilized for heating this air before its admission into the turbines, which consists in maintaining, for small loads the speed of the auxiliary turbine at that value which corresponds to full load conditions and controlling the relative amounts of combustion products supplied to the two turbines, respectively, in accordance with the load variations of the motive turbine, whereby the motive turbine can rapidly respond to an increase in the load.

2. The method of operating a thermal gas turbine motor comprising a motive turbine capable of delivering power, an auxiliary turbine mechanically independent of the motive turbine, an air compressor driven by the auxiliary turbine and supplying air to the said turbines and a combustion chamber utilized for heating this air before its admission into the turbines, which consists in maintaining, for a small load, the speed controlling the relative amounts of combustion lproducts supplied to the two turbines, respectively, in accordance with the load variations of the motive turbine, whereby the motive turbine can rapidly respond to an increase in the load.

3. In a thermal gas turbine motor comprising a motive turbine capable of delivering power, an auxiliary turbine mechanically independent oi' the motive turbine, an air compressor driven by the auxiliary turbine and supplying air to the said turbines, a combustion chamber, receiving a certain .fuel supply and utilized for heating this air before its admission into the turbines, a device for distributing power between the auxiliary turbine and the motive turbine in order to cause to vary the hot gas currents which respectively reach the auxiliary turbine and the motive turbine comprising means to control the flow of the not gas current to the auxiliary turbine, a speed governor connected to the auxiliary turbine and controlling this device and a speed governor driven by the motive turbine and controlling the fuel supply to the combustion chamber.

4. In a thermal gas turbine motor comprising a motive turbine capable of delivering power, an auxiliary turbine mechanically independent of the motive turbine, an air compressor driven by the auxiliary turbine and supplying air to the said turbine, a combustion chamber utilized for heating this air before its admission into the turbines and which receives a. certain supply of fuel, a device for distributing the power between the auxiliary turbine and the motive turbine in order to cause to vary the hot gas` currents which respectively reach the said turbines, a speed governor connected to the'auxiliary turbine and controlling this device, a speed regulator driven by the motive turbine and controlling the supply of fuel fed to the combustion chamber and connecting means between the latter governor and the device for distributing the power whereby the governor of the motive turbine eiects an approximate adjusting of this device which is then perfected by the speed governor of the auxiliary turbine.

5. In a gas turbine motor comprising a motive turbine capable of delivering power, an auxiliary turbine mechanically independent of the motive turbine, an air compressor driven by the auxiliary turbine, a combustion chamber receiving a part of the air current from the compressor in order to heat this air before its admission into the auxiliary turbine, a second combustion chamber receiving the other part of the air from the compressor in order to heat this air before its admission into the motor turbine, fuel supply means for the said chambers, a speed governor driven by the auxiliary turbine and controlling the fuel supply fed to the rst mentioned combustion chamber, a speed governor driven by the motive turbine and controlling the fuel supply to the second mentioned combustion chamber as Well as the fuel supply reaching the rst combustion chamber, so that the said fuel supply is rst adjusted in an approximate manner by the speed governor of the motive turbine and then adjusted in a precise manner by the speed governor of the auxiliary turbine.

6. In a thermal gas turbine motor comprising a. motive turbine capable of delivering power, an auxiliary turbine mechanically independent of the motive turbine, an air compressor driven by the auxiliary turbine and Supplying the air to the said turbines, means for heating this air before its admission into the turbines, said heating means receiving a certain fuel supply, a device for distributing the power between the turbines, a speed governor driven by the auxiliary turbine, a balance-lever which can oscillate about a pivot, the said balance lever constituting means for transmitting movement between the said speed governor and the device for distributing the power, means for adjusting the position of the pivot so as to modify the displacement of the device for distributing the power for the same displacement of the said speed governor, and a speed governor driven by the motive turbine and controlling the fuel supply to said heating means,

7. In a thermal gas turbine motor comprising a motive turbine capable of delivering power, an auxiliary turbine mechanically independent of the motive turbine, an air compressor driven by the auxiliary turbine and feeding the air to the said turbines, at least one combustion chamber utilized for heating this air before its admission into the turbines and receiving a certain fuel supply, a device for distributing the power between the turbines, a speed governor driven by the auxiliary turbine, a balance-lever capable of oscillating about a pivot, the said balance-lever being connected by one of its extremities to the said speed governor, means movable in relation to the load on the motive turbine and connected with the other extremity of the said balance lever. the said balance-lever being connected moreover, at an intermediary point to said device for distributing the power, means for varying the position of the said pivot so as to modify the displacement of therdevice for distributing the power for the same displacement of the said speed-governor and a speed-governor driven by the motive turbine and controlling the fuel supply reaching the said combustion chamber.

LOUIS ARMAND HERMITI'E. 

